Piano.



O. JOHNSON.

PIANO.

urmornon FILED MAR. 6, 1909.

1,032,608. Patented July 16, 1912.

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AAAAAAAAAAAAAAAAA H 60., WASHINGTON. n. c.

G. JOHNSON.

PIANO.

nrmoynon FILED ma. 6, 1909.

1,032,608. v Patented July 16, 1912..

2 SHEETSSHEET 2.

COLUMBIA PLANOORAPH 20., WASHINGTON, D. c.

CARL JOHNSON, OF ST. PAUL, MINNESOTA.

PIANO.

Specification of Letters Patent.

Application filed March 6, 1909.

Patented July 16,1912.

Serial No. 481,795.

To all whom it may concern:

Be it known that I, CARL JOHNSON, a cit1- zen of the United States,residing at St. Paul, in the county of Ramsey and State of Minnesota,have invented a new and useful Improvement in Pianos, of which thefollowing is a specification.

My invention relates to improvements in pianos and more particularly tothe sounding board thereof.

The object of my invention is to produce in a piano a better quality oftone and provide means for tuning up the sounding board of a piano whenit has lost some of its resonant qualities.

Further objects are to reduce the weight of the piano, permit the pianoto be easily knocked down for shipment or other purposes and produce apiano which is strong, durable, simple and inexpensive.

In a general way, my invention comprises a string plate made out of asingle piece of metal in which the sounding board and pin block aredetachably fastened under stress. Heretofore the parts of the soundingboard have been fastened to the case by means which has not permittedthe parts to be easily detached and further the string frame has beenweak in construction where any attempt has been made to hold the pinblock and sounding board by a single piece of metal. With my inventionthe string plate may be made of any desired strength and is adapted tohold the pin block and sounding board without working loose and changingthe tone quality of the piano.

In the accompanying drawings, forming part of this specification Figure1 is a plan view of a horizontal grand piano, with'the cover removed todisplay my invention; Fig. 2 is a detail section of Fig. 1 on the lineXX, and Fig. 3 is a view looking up at the sounding board.

In the drawings A represents a piano case or frame which may be madeshallow as compared with those in use prior to my invention.

B represents a pair of sounding boards made with two separate parts 2and 3 which are held in a rim or flange 4c of a string plate C and maybe arched to improve tone qualities as desired. The rim or flange isintegral with the string plate and is continuous around the periphery ofthe sounding boards, being formed at substantially right angles with theplane of the plate.

The inner face 13 of the rim at against which the edges of the soundingboards impinge, is beveled outwardly. In assembling the parts thesounding boards 2 and 3 are sprung into the rim a under pressure and arespaced apart and from the string plate 5 by spacing blocks 9 which maybe varied in thickness. A flanged plate 1.2 lies below the lower block 9and is bolted to the string plate C by bolts 11 which pass through theflange plate, the blocks 9, the boards 2 and 3, and the string plate C,and by means of which the sounding boards 2 and3 are forced into the rim4. In this way the sounding boards are held in position under acompressive stress in the plane of the board. Tie bars l0 lie beneaththe sounding board B and have hook ends 14- passing through the edge ofthe rim 4 and engaging the same to stiffen it. The tie bars are attachedto the string plate by the bolts 11. Restbars 15 are attached to thecase of the piano by bolts 17 and carry the rim a of the string plate,thus assisting in supporting the sounding board. The string plate itselfis attached to the case of the piano by screws 16. Thest-ring plate isformed with an extension 6 which is adapt ed to hold a pin block 7, thelatter being secured to said extension by bolts 8. Flanges 2O integralwith the string plate extend beneath the extension 6 and serve tostiffen the attachment of the pin block. The piano strings, not shown,are fastened to the pin block and string plate in the ordinary manner.This construction permits the easy removal of the string plate from thepiano case, while the sounding boards can be taken from the string platewithout unstringing the instrument, by removing the tie bars 10, and thebolts 11 from the flange rim 12 and lifting the boards from. the socketformed by the rim 4.

It is obvious to those skilled in the art to which this inventionrelates that the parts thereof may be variously changed and modifiedwithout departing from the spirit thereof, and I do not confine myselfto the exact construction described within the scope of the followingclaims.

In accordance with the patent statutes I have described the principlesof operation of my invention together with the apparatus which I nowconsider to represent the best embodiment thereof but I desire to haveit understood that the construction shown is only illustrative and thatthe invention can be carried out by other means and applied to usesother than those above set forth within the scope of the followingclaims.

Having described my invention, what I claim as new and desire to protectby Letters Patent is 1. In a piano, a string plate formed in one piecehaving a flange entirely about the outer edge of the back thereof anddisposed at substantially right angles thereto and forming an inclosingwall, the inner surface of said flange flaring outwardly, a soundingboard disposed substantially parallel with said string plate andconfined by said flange with the outer edge of the sounding boardbetween the sounding board and the string plate, and means for forcingsounding board engaging the flaring surface of said flange, a stopwithin said flange 'between the sounding board and the string plate, andmeans for forcing said sounding board inwardly along the flaring surfaceof said flange against said stop; whereby a certain compressive stressin the board may be secured.

2. In a piano, a singlepiece string plate formed with a continuousreinforcing flange at substantially right angles to the back thereof,the inner surface of said flange flaring outwardly, a sounding boardconfined by said flange and means for securing said board with its outeredge forced inwardly along the flaring surface of said flange, whereby acirculnferentially continuous wedging effect is produced, for-thepurposes specified.

In testimony whereof, I have signed my name to this specification, inthe presence of two sitibscribing witnesses.

CARL JOHNSON.

\Vitnesses J. T. AVERY, F. G. BRADB'URY.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. 0.

